add docs for overriding partials (#898)

source/customizations.rst

@@ -154,6 +154,8 @@ This will result in a CSS tag added to all dashboard pages with the path: ``/pub
 
 .. _help_menu_guide:
 
+.. include:: customizations/overriding-partials.inc
+
 Add URLs to Help Menu
 ---------------------
 

source/customizations/overriding-partials.inc

@@ -0,0 +1,41 @@
+.. _overriding-partials:
+
+
+Overriding Pages
+----------------
+
+Open OnDemand is built with Ruby on Rails which uses ``partials``
+to build the web pages that are ultimately served to the clients.
+
+All partials are held within `dashboard's views folder`_.  These
+are the default ``partials`` that get distributed when you install
+the package.
+
+Open OnDemand provides a facility to override any of these partial
+pages by supplying new files in ``/etc/ood/config/apps/dashboard/views``.
+
+Let's look at an example where a center can provide a different,
+specialized, footer for the bottom of the page. Overriding the
+``partial`` that has been distributed.
+
+First, you would need to find the original ``partial`` that is being
+distributed.  
+
+We can find this file's location at ``layouts/_footer.html.erb``
+(relative to the `dashboard's views folder`_).
+
+To override it, we simply provide a new file of the same name
+and path in the ``/etc/ood/config/apps/dashboard/views`` folder.
+
+So, the full file path would be ``/etc/ood/config/apps/dashboard/views/layouts/_footer.html.erb``.
+By providing a simple html file like the one below, placed in the location in the
+previous sentence, your center has now provided a different footer than the one
+distributed by the Open OnDemand package.
+
+.. code-block:: html
+
+  <div class="text-center h-5 my-3" >
+    My center's custom footer.
+  <div>
+
+.. _dashboard's views folder: https://github.com/OSC/ondemand/tree/master/apps/dashboard/app/views